m.youtube.com/watch?v=5Nsk-XY5j4c
It has some of the same steps as the rooting videos
First thing he was doing was making a Titanium backup which you need to be rooted to use. This backups your apps which you can restore even when switching ROMs which makes it less of a hassle when switching ROMs since you don't have to configure all your apps. You'll just have to setup the system settings like ringtones, wifi passwords etc.
After that he was downloading the ROM from an app called Goo Manager. Not all ROMs can be found on this app so if it's not there that doesn't mean you can't get it elsewhere.
Then he was making a nandroid backup which backs up
everything in case you screw something up and want to go back to the way your phone was at the time of that backup. It's also useful if you want to try out a new ROM but aren't sure if you'll like it or not. With a nandroid you can try out ROMs and if you don't like them or they don't work well then you can go back to your nandroid.
Lastly he was flashing CM. So no, that video doesn't show you how to unlock the bootloader (if your phones bootloader is locked you won't be able to install a custom ROM), how to root the phone and how to install a custom recovery (for easily flashing ROMs and making nandroid backups directly on the phone without the need of a computer).